add library to arduino Library Manager

[s-light]

please add your library to the Arduino Library Manager:
https://github.com/arduino/library-registry/blob/main/README.md#adding-a-library-to-library-manager

its fast and benefits the users :-)

requirements for successful add...)

i checked - and currently its not in the list

[s-light]

thank you for writing this library!

i have done the submission as i like to give easy instructions for my pupils:
arduino/library-registry#5243

so the library should be available for installation via the IDE in about a day.

the current state can be checked at:
https://downloads.arduino.cc/libraries/logs/github.com/codingABI/DFR0534/

the Arduino Lint tool had one improvement:

Linting library in DFR0534
WARNING: Incorrect Arduino.h filename case in #include directive: 
DFR0534/src/DFR0534.h:24: #include <arduino.h> (Rule  LC001)                                                                                                         

Linter results for project: 0 ERRORS, 1 WARNINGS

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Linting sketch in DFR0534/examples/playCombined

Linter results for project: no errors or warnings

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Linting sketch in DFR0534/examples/playFileByName

Linter results for project: no errors or warnings

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Linting sketch in DFR0534/examples/playFileByNumber

Linter results for project: no errors or warnings

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Linter results for projects: 0 ERRORS, 1 WARNINGS